Fuse



Feb. 22, 1949.

D. R. BEI-:MAN 2,462,062

FUSE

Filed June 23, 1942 D nnuld-R-E1eem11n uern/bm;

@fw @i @M 7M @M Patented Feb. 22, 1949 UNITED STE FUSE Donald R. Beeman, Wharton, N. J., assignor to the United States of America as represented by the Secretary of War (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 1A Claim.

Y The invention described herein may be manufactured and used by or for the Government for governmentalpurposes, without the payment to me of any royalty thereon.

This invention relates to a fuse. and in particular to a type carrying a separable portion of a powder train in a centrifugally movable housing.

It is an object of the invention to provide such a fuse which shall have improved safety in the event of premature setting off of the detonator. More specifically it is an object of the invention to provide such a fuse in which the centrifugal member is sealed in its slide passageby the forces of premature explosion of the detonator. It is a further object of the invention to provide improved means of retaining the.'centrifugal'memberV in armed position after normal functioning;

These and other objects are attained by loeating the detonator; closely.' adjacent the slide passageY containing theA centrifugal member with only a small webotmaterial in the fuse body between the two which web is easily forced into gastight engagement with the centrifugal member to prevent passage of gaseous detonation products to the oiTset portion of the powder train. The sliding member is retained in armed position by means of a ball which drops into a circular groove either under centrifugal action or creep.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is an elevational View in axial section of a fuse housing, and

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1.

Referring to the drawing by characters of reference, there is shown a fuse body I containing a forwardly located booster 2 retained by a screwed cap 3 with sealing disk 4. A central longitudinal bore 5 passes through the body I and serves as a firing communication with the booster. An oblique bore 6 of substantially larger diameter than the bore 5 intersects the central bore 5 and has an eccentric counterbore 'I to accommodate the eccentric head 8 of a sliding bolt 9 in the bore 6. The bore 6 is inclined from its open end toward the rear at an angle approximating (though not necessarily) twenty degrees to a plane normal to the longitudinal axis of the body I, and this bore extends across 2 the bore 5- and beyond a distance of approxi'- mately three times the diameter of the bore 5 to a blind and stopping short of the periphery of the body I a substantial distance. A tapped counterbore I9 concentric with eccentric counterbore l receives a closure cup nut II which serves as a seat for a spring I2 engaging around a central boss I3 on the eccentric head 8 of the bolt 9. An obliquely transverse bore I4 in the bolt 9 contains a portion of the booster charge 2 or other iire communicating medium, this bore being maintained in parallelism withthe central bore 5 of the fuse body by the eccentricity of the sliding bolt head Sand the counterbore 'I.

A rst counterbore I5 in the other end ofthe central bore 5 receives a washer I6 and a detonator il. A second counterbore I8 isthreaded to receive a detonator-retaining ring I9 and a third counterbore 29 is threaded to receive a head portion 2I of the fuse. A central bore 22 in the inner end of the head portion recevesa hammer plunger 23 of substantial mass for movement by inertia. Fitted in a .radial slot 24 in the plunger is a centrifugal block hammer 25 rotatably mounted in the plunger on a transverse axis intersecting the axis of the fuse by a pin 26. The hammer 25 has parallel sides normal to the pin 25, and is fitted in the slot so that these sides lie equally spaced from the axis of the fuse. The hammer 25 has a bore 21 rearward of the pin 26 at initial or unarmed position of the hammer receiving pins 28 which are initially engaged in and slidable radially under centrifugal action into bores 29 in the plunger so as to clear the hammer, but are normally held in hammer locking position by means of springs 30 conned in the bores 29. A sleeve 3l around the plunger retains the pins 28 and is secured by a pin 32. The plunger is held in the rearward position in the bore 22 by means of a spring 33 fitted in a bore 3S in the plunger and in a guide tube 35 carried by the body I4, which guide tube is also slidably engaged in the bore 34. The plunger and hammer correspond to prior known devices of similar function, the hammer having a firing pin thereon which projects laterally out of line with the detonator at initial (safe) position of the hammer, but moving into line with the detonator under centrifugal force.

The bottom of the counterbore I5 is located adjacent the oblique bore 6 and this results in a relatively thin web portion 36 between the detonator Il and the inner end portion of the bore 6. This web portion is deformable by explosion of the detonator Il when the products of such explosion are conned by the bolt 9. A cavity 3l in the oblique bolt 9 forms a prolongation of that portion of the central bore or flash hole 5 which is between the primer and the oblique bolt. A ball 38 is received in a cavity 39 in the forward side of the bolt 9, and a counterbore lll)y in the nut Il is of suflcient diameter to receive the ball 38 freely under centrifugal action and creep eiects. It should be noted, however, that the radius of the counterbore 40 is such-that the ball 38 is prevented from escaping entirely from the cavity 39, so that while the ball engages the wall of the bore 40, any tendency of the bolt 9 to return will be prevented by engagement of the ball between the rear side of the cavity and opposing inner end surface of the counterbore l0.

The construction shown4 renders the fuse safe Y ucts must follow to reach the displaced ignition train would be between the bolt 9 and the abutting surface of the bore 6, commencing at the central bore 5. Any premature explosion of the detonator prior to sliding of the bolt 9 into armed position would result in a forcing of the web structure 36 against the bolt 9 resulting in an effective seal of the only path to the offset part of the ignition train carried in the bore I4 through the bolt. The provision of cavity 31 in the slide bolt 9 permits by-passing of the path to the powder train for a very brief interval to ensure that no gases will enter between the bolt and its housing prior to sealing ofthe web. If

these gases were permitted to enter between the bolt and surface of the bore 6, a balancing pressure might be set up which would militate against the keffective sealing of the web.

I claim:

A fuse comprising a body portion having a re communicating passage, a bolt receiving bore across said passage and at an oblique angle thereto, a bolt slideably moveable in said bore between extreme armed Vand unarmed positions.

a second fire-communicating passage in said bolt alignable with the first re communicating passage in the armed position but rearwardly slideable down said bore in the unarmed position, a detonator in said body in communication with the first fire communicating passage, a portion of the material of said body extending between said detonator and said bolt immediately adjacent to said bolt, said portion being constructed to yield to the pressures produced by the explosion of the detonator when fired while the bolt is in said safe position, whereby to seal the opening between said bolt and said body portion against passage of gases on premature approach of said detonator when said bolt is in the safe position, a cavity in said bolt at its forward side, a sphere loose in said cavity, and a receiving groove for said sphere in said body portion rto lock the bolt against return sliding, said groove being of a depth substantially less than the diameter of the sphere, said cavity being spaced from said'groove whenthe bolt is in said safe position a distance equal to the distance between said safe position and said armed position of the bolt, whereby `under the combined action of creep and centrifugal force said sphere is urged toward said groove when said bolt is in the arnied position.

DONALD R. BEEMAN.

'REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,310,792 LaVal July 22, 1919 1,463,747 Lowman July 31, 1923 1,569,248 Adelman Jan. 12, 1926 2,402,702 Woodberry June 25, 1946 FOREIGN PATENTS Number Country Date 548,039 Great Britain Sept. 23, 1942 

